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%I #21 Aug 16 2020 21:20:17
%S 0,0,0,0,0,0,0,0,1,0,0,1,0,0,4,0,0,4,0,0,10,0,0,11,0,0,22,0,0,25,0,0,
%T 44,0,0,51,0,0,83,0,0,98,0,0,149,0,0,177,0,0,259,0,0,309,0,0,436,0,0,
%U 521,0,0,716,0,0,857,0,0,1151,0,0,1376,0,0,1816,0,0,2170,0,0,2818,0,0
%N Number of partitions of n into parts 6k and 6k+3 with at least one part of each type.
%H Robert Price, <a href="/A035639/b035639.txt">Table of n, a(n) for n = 1..999</a>
%F G.f. : (-1 + 1/Product_{k>=0} (1 - x^(6 k + 3)))*(-1 + 1/Product_{k>=1} (1 - x^(6 k))). - _Robert Price_, Aug 12 2020
%t nmax = 83; s1 = Range[1, nmax/6]*6; s2 = Range[0, nmax/6]*6 + 3;
%t Table[Count[IntegerPartitions[n, All, s1~Join~s2],
%t x_ /; ContainsAny[x, s1 ] && ContainsAny[x, s2 ]], {n, 1, nmax}] (* _Robert Price_, Aug 12 2020 *)
%t nmax = 83; l = Rest@CoefficientList[Series[(-1 + 1/Product[(1 - x^(6 k)), {k, 1, nmax}])*(-1 + 1/Product[(1 - x^(6 k + 3)), {k, 0, nmax}]), {x, 0, nmax}], x] (* _Robert Price_, Aug 12 2020 *)
%Y Cf. A035441-A035468, A035618-A035638, A035640-A035699.
%Y First trisection gives A006477.
%K nonn
%O 1,15
%A _Olivier GĂ©rard_